Description

In JetBrains IntelliJ IDEA before 2026.3 opening arbitrary URLs without confirmation was possible via the Remote Development port forwarding model

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.7",
  "pubDate": "2026-11-06T17:17:22.397Z",
  "pubdate": "2026-11-06T17:17:22.397Z",
  "executiveSummary": "A vulnerability exists in the Remote Development port forwarding mechanism within JetBrains IntelliJ IDEA versions prior to 2026.3, allowing for unauthorized redirection to arbitrary URLs.\nThe vulnerability is classified as an improper handling of remote URI requests, which bypasses mandatory user confirmation processes.\nThe impact involves an attacker's ability to force a user's development environment to interact with malicious external resources, potentially leading to unauthorized data exfiltration, credential harvesting, or the execution of web-based payloads through the trusted development context.\nThis issue affects users utilizing Remote Development features, where the lack of an explicit confirmation gate allows an attacker to direct traffic without user awareness.\nThe risk is elevated due to the implicit trust users place in their IDE environment, and exploitation does not require advanced administrative privileges beyond access to the remote project configuration or the triggering mechanism.",
  "technicalDetails": "The root cause of this vulnerability lies in the Remote Development port forwarding model's handling of outgoing traffic requests, specifically the lack of a validation or confirmation gate when initiating connections to external URIs.\nIn IntelliJ IDEA environments, the Remote Development feature manages port forwarding to expose host services to the guest or vice-versa. During the negotiation or redirection phase of these connections, the application fails to verify the destination URL against a whitelist or enforce an interactive user confirmation step.\nThe attack flow begins when an attacker influences the remote environment configuration or triggers a specific sequence within the IDE’s internal URI handling mechanism. By injecting a crafted URL into the port forwarding request, the attacker leverages the IDE's legitimate communication channels to establish an outbound connection.\nBecause the IDE treats these requests as legitimate parts of the project's development workflow, the request is dispatched without triggering security warnings. This allows the remote server—or an attacker controlling the request parameters—to navigate the user's browser or IDE-embedded web view to an arbitrary location.\nThe vulnerable component is identified as the Remote Development gateway responsible for mediating network communication between the local client and the remote host environment.\nThe impact is significant, as the IDE often maintains sessions with high-privilege access, such as SSH keys or API tokens, stored in the environment. An attacker can use this redirection to perform Cross-Site Request Forgery (CSRF) or initiate a browser-based attack on the user's local machine, leveraging the context of the running IDE process to bypass standard security headers or site isolation policies.\nThis vulnerability persists across all IntelliJ IDEA versions released prior to 2026.3. Exploitation is typically facilitated by the IDE’s inherent trust in internal project settings and the Remote Development configuration, making it difficult for standard end-users to detect during routine activity."
}